The PRIME Algorithm: A Game-Changer for Early Rectal Cancer Management

Key Learning Points

• Pocket Detection Method (PDM): Creating a submucosal pocket allows direct visualization of the tissue planes and assessment of invasion depth before committing to a resection strategy
• Muscle Retraction Sign (MRS): Recognition of this critical sign indicates muscle involvement and signals the need to change from standard ESD to intermuscular dissection
• Deep Margin Optical Diagnosis: Real-time assessment of the relationship between lesion, submucosa, and muscle layer guides plane selection
• Endoscopic Intermuscular Dissection (EID): When MRS is detected, EID allows dissection between circular and longitudinal muscle layers for adequate margins
• R0 as the Goal: The algorithm emphasizes achieving clear margins rather than accepting the excisional biopsy mindset

The PRIME Algorithm in Practice

The procedure begins with careful lesion assessment. In this case, the lesion displays BLINK positivity, central depression, and converging folds - features concerning for deep invasion. Rather than proceeding directly with standard ESD, the operator creates a pocket to assess the submucosal plane.

Upon identifying the muscle retraction sign during pocket creation, deep margin optical diagnosis confirms the need to change planes. The decision to switch to EID is made in real-time, demonstrating the adaptive nature of the PRIME algorithm.

REACT Tool Integration

This case demonstrates integration of the REACT tool for procedural support, highlighting how digital resources can enhance complex endoscopic procedures.

Who Should Watch

This video is essential viewing for interventional endoscopists managing rectal lesions, particularly those looking to expand beyond standard ESD into intermuscular dissection techniques. The surgical-endoscopic collaboration also provides valuable anatomical perspectives for understanding safe dissection zones.